Arnold is seen at Mr. Ruhle's office during one shot, although he is seen inside the chick's egg. But in the next shot, Carlos is seen.
(desperate to get the kids out of the egg, Liz cracks it on her forehead)
Carlos: Hey, Liz, you've got egg on your face!
Kids: And us!
DA kisses Arnold on the cheek after his heroics as the chicken.
Title: Cracks a Yolk
When someone says a joke, some people say that they crack a joke.